Audio recorder



Feb. 4, 1964 1. BREGMAN 3,120,392

AUDIO RECORDER Filed April 15, 1960 2 g1 -20E 20c 5 INVENTOR. Y5 20A mvm EREGMAN 2 Q United States Patent 3,120,392 AUDHB REtIlIRDER Irvin Bregrnan, Plainfieid, NJ. (22 Hamilton Court, Stamford, Conn.) Filed Apr. 15, 196i). Ser. No. 22,592 4 Claims. (Cl 274-20) This invention relates to an audio recording device or more specifically to an audio recorder of such character suitable for preparing recordings of the type required and described in my co-pending patent application entitled, Combination Photograph-Disc Record Unit and Automatic Exhibiting and Playing Means Thercfor, Serial No. 696,435, dated November 14, 1957.

To prepare the record the photographer dictates his message and thus mechanically modulates a blank while cutting a spiral groove. At the completion of the commentary a means must be provided to trigger a solenoid operated clutch so that the next slide in sequence can be cycled. Numerous methods have been employed in audio slide projectors to initiate the change cycle. For example, frequency sensitive circuits or photoelectric effects have been used. However, because of its greater reliability and simplicity I have selected a mechanical means for triggering the clutch. That is, when the tone arm reaches a fixed distance from the center of the disc it closes a micro switch to energize the solenoid.

In projecting a series of slides it is desirable to have the interval of time between slides as short as possible accordingly the pitch of the ecent-ric spiral must be increased greatly at the conclusion of the commentary so that the tone arm will rapidly move to the solenoid triggering position. The transition from the recorded spiral to the steep eccentric spiral must be smooth and continuous other-wise the stylus will not follow the groove.

In experimenting with my projector I have searched the market for a simple commercially available mecha nism to cut both the modulated groove and the steep eccentric spiral and find this equipment unavailable to the amateur recordist or photographer.

The primary object of this invention is to provide a simple, compact, easily operable mechanism for cutting both a narrow pitch modulated spiral for recording and a large pitch spiral for quick triggering.

Other objects of the present invention will be apparent to those skilled in the art by the ensuing disclosure and accompanying drawings in which:

FIGURE 1 is a top plan view of the recorder with a section broken away to reveal details of the mechanism.

FIGURE 2. is a section taken on line 3-3 of FIG- URE 1.

FIGURE 3 is a fragmentary sectional view taken on line 4- 1 of FIGURE 1.

Referring to FIGURES 1 and 2 a gear motor 5 and motor pulley 6 are mounted on the underside of bedplate 4. The motor shaft 9 extends thru the bedplate 4 to form the spindle for turntable 8. Worm gear 7 is driven thru a belt 53- from pulley 6. Recording arm 10 is equipped with a standard recording cartridge 51 stylus 51 tension adjustment means 52 and level adjustment means, now shown. Also affixed to the tone arm 10 is follower 11. Follower 11 rides on lead screw 12 when the tone arm is in the recording or horizontal position but when the tone arm 11} is lifted to the vertical or neutral position by pivoting about guide shaft 13 the follower 11 disengages from the lead screw 12 and the recorder arm it is free to slide along guide shaft 13. Lead screw 12 is axially loaded by the force of spring 14, so that the end of lead screw 12 always bears upon a wedge shaped face cam 15 thru ball 16. However, lead screw 12 can move axially and this is accomplished when face cam 15 is rotated. The amount of axial translation of lead 3,12%,392 Patented Feb. 4, 1964 screw 12 is determined by the amount of rotation of face cam 15. Rotating face cam 15 counterclockwise overrides spring 14 and forces lead screw 12 in the hearing 55. This causes the lead screw 12 to move axially into the assembly. Or, if the face cam 15 is rotated in the clockwise direction the spring 14 forces lead screw 12 out of the assembly by an amount dependent upon the pitcth and degree of rotation of cam 15.

The lead screw shaft 12 has machined upon it a worm wheel 54 with exceptionally long threads so that smooth,

jerkless engagement between worm 7 and worm wheel 54 will be achieved even when the lead screw 12 is being axially translated and rotated simultaneously. A handle 18 on cam 15 is free to rotate about pin 19. Handle 18 is spring loaded so that in effect it also serves as a detent and when rotated counterclockwise it will engage any one of cavity 26A, 208 or 29C shown on FIGURE 3.

To clarify the use of the mechanism it would be well to trace a recording cycle. With the tone arm 10 in its vertical position relative to turntable 8 a record blank is placed upon turntable 8. The record blank can be secured to the turntable in any manner which will prevent slippage between the turntable and record blank. In the model which I have built I have threaded the spindle 9 and secured the record to the turntable by fastening a nut over it.

The motor is then started, and the tone arm 10 is tilted to its horizontal or recording position so that stylus 51 rests upon the record blank at its outermost periphery. In this position the lead screw follower 11 is in contact with lead screw 12. For best results it is desired to cut a steep pitch spiral before recording starts and another steep pitch spiral after recording is completed. The former steep spiral spans an annulus about inch in width. Its purpose is to permit the playback stylus to engage the groove over an area considerably larger than the width of a single modulated groove. The two steep spirals and the modulated groove must form one continuous smooth groove. To cut this initial spiral, handle 18 is moved from its initial position in cavity 20A to 2013. The angular distance between MA and 20B is of such dimensions so that movement of handle 18 from cavity ZilA to cavity 23B will advance the lead screw 12 into the bearing 55 about inch and this will cause a steep pitch spiral about inch in width measured from the outer periphery to be out upon the record. The commentary is then dictated into the machine in the usual manner. Upon the completion of the modulated portion of the recording, handle 13 is moved slowly from cavity 20B to 26C. This again permits face cam 15 to rotate and drive lead screw 12 further into the assembly against spring 14, carrying tone arm 111 with it to again cut a steep pitch eccentric spiral. By proper selection of spring, worm and worm wheel and lead screw pitch, one can achieve ratios between recording pitch and eccentric spiral pitch of several hundred to one.

At the completion of the final spiral the tone arm 10 is lifted to the vertical position, slid along guide shaft 13 to the start position so that it will he in place for the next recording. The motor 5 is then stopped and the record removed from the turntable 8. The handle 18 is returned to its start position by rotating it counterclockwise until handle 18 again engages cavity 213A and the mechanism is now ready for the preparation of a new recordmg.

While the preferred embodiment of this invention has been disclosed, it will be apparent to those skilled in the art that there are many modifications possible other than the one illustrated and described which may accomplish the above mentioned results. For this reason it should be kept in mind that this embodiment is only illustrative of this invention and that as long as modifications do not depart from the scope of the appended claims and the spirit of this invention, such modifications come Within this invention.

Having described my invention what I claim is:

1. In an audio recorder for recording on a fiat disc record, an improved means for radially advancing a recording cartridge across such a flat disc record at a rate correlated with the rotational velocity of such record as to produce a modulated groove and a steep spiral end portion and start portion; said means comprising an integral combination wormwheel-leadscrew shaft having a wormwheel cut on one portion thereof and a leadscrew cut on another portion thereof; means for mounting said shaft for rotational and axial movement; a power-driven worm mounted for engagement with said wormwheel for rotating said shaft; a leadscrew follower operatively connected to said recording cartridge for cooperating with said leadscrew for causing radial movement of said cartridge upon rotation of said shaft; and means for axially moving said shaft whenever desired.

2. Apparatus as defined in claim 1 wherein said last mentioned means comprises means for resiliently urging said shaft in an axial direction; a cam means positioned to oppose the thrust of said resilient means; and means for moving said cam to vary the axial position of said shaft against the opposing force of said resiliently urging means.

3. Apparatus as defined in claim 2 wherein said means for moving said cam is provided with stop means for stopping said cam at discrete positions.

4. An audio recorder of the character described comprising a motor mounted uopn a bedplate, a motor shaft extending thru said bedplate and a turntable mounted thereon; a spindle provided on said turntable for centering and securing a blank recording disc; a pulley mounted on said motor shaft, said pulley coupled to a worm shaft thru a drive belt, said worm shaft co-operating with a combined wormwheel-leadscrew shaft, said Wormwheclleadscrew shaft being of such nature as to permit simultaneous axial translation and rotation, said wormwheelleadscrew shaft being spring loaded axially, and cam means bearing axially and opposing said spring on said combination wormwheel-leadscrew for axially translating said Wormwheel-leadscrew shaft; start means and stop means associated with said cam for fixedly positioning wormwheel at discrete positions; a recording arm assembly comprising a recording cartridge with a stylus, a stylus adjusting means and a leadscrew follower; said leadscrew follower pivotally mounted and slidable on a guide shaft, said guide shaft being essentially parallel to said leadscrew, said follower pivotally engageable with said leadscrew and translatable when engaged with said leadscrew when said leadscrew is translated or rotated.

References Cited in the file of this patent UNITED STATES PATENTS 2,071,972 Feyrer Feb. 23, 1937 2,082,353 Proctor June 1, 1937 2,340,658 Goldman Feb. 1, 1944 2,714,010 Gruber et a1. July 26, 1955 FOREIGN PATENTS 746,243 Great Britain Mar. 14, 1956 

1. IN AN AUDIO RECORDER FOR RECORDING ON A FLAT DISC RECORD, AN IMPROVED MEANS FOR RADIALLY ADVANCING A RECORDING CARTRIDGE ACROSS SUCH A FLAT DISC RECORD AT A RATE CORRELATED WITH THE ROTATIONAL VELOCITY OF SUCH RECORD AS TO PRODUCE A MODULATED GROOVE AND A STEEP SPIRAL END PORTION AND START PORTION; SAID MEANS COMPRISING AN INTEGRAL COMBINATION WORMWHEEL-LEADSCREW SHAFT HAVING A WORMWHEEL CUT ON ONE PORTION THEROF AND A LEADSCREW CUT ON ANOTHER PORTION THEREOF; MEANS FOR MOUNTING SAID SHAFT FOR ROTATIONAL AND AXIAL MOVEMENT; A POWER-DRIVEN WORM MOUNTED FOR ENGAGEMENT WITH SAID WORMWHEEL FOR ROTATING SAID SHAFT; A LEADSCREW FOLLOWER OPERATIVELY CONNECTED TO SAID RECORDING CARTRIDGE FOR COOPERATING WITH 